Targeting HIF-1α with Specific DNA Yokes for Effective Anticancer Therapy.

Hypoxia, a ubiquitous hallmark in cancer, underscores the significance of targeting HIF-1α, the principal transcriptional factor of hypoxic responses, for effective cancer therapy. Herein, DNA yokes, a novel class of DNA nanomaterials harboring specific HIF-1α binding sequences (hypoxia response elements, HREs), are introduced as nanopharmaceuticals for cancer treatment. Comprising a basal tetrahedral DNA nanostructure and four HRE-bearing overhanging chains, DNA yokes exhibit exceptional stability and prolonged intracellular retention. The investigation reveals their capacity to bind HIF-1α, thereby disrupting its interaction with the downstream genomic DNAs and impeding transcriptional activity. Moreover, DNA yokes facilitate HIF-1α degradation via the ubiquitination pathway, thereby sequestering it from downstream targets and ultimately promoting its degradation. In addition, DNA yokes attenuate cancer cell proliferation, migration, and invasion under hypoxic conditions, while also displaying preferential accumulation within tumors, thereby inhibiting tumor growth and metastasis in vivo. This study pioneers a novel approach to cancer therapy through the development of DNA-based drugs characterized by high stability and low toxicity to normal cells, positioning DNA yokes as promising candidates for cancer treatment.

Gelatin-Encapsulated Tetrahedral DNA Nanostructure Enhances Cellular Internalization for Treating Noise-Induced Hearing Loss.

Nanoparticle-based drug delivery strategies have emerged as a crucial avenue for comprehensive sensorineural hearing loss treatment. Nevertheless, developing therapy vectors crossing both biological and cellular barriers has encountered significant challenges deriving from various external factors. Herein, the rational integration of gelatin nanoparticles (GNPs) with tetrahedral DNA nanostructures (TDNs) to engineer a distinct drug-delivery nanosystem (designed as TDN@GNP) efficiently enhances the biological permeability and cellular internalization, further resolving the dilemma of noise-induced hearing loss via loading epigallocatechin gallate (EGCG) with anti-lipid peroxidation property. Rationally engineering of TDN@GNP demonstrates dramatic alterations in the physicochemical key parameters of TDNs that are pivotal in cell-particle interactions and promote cellular uptake through multiple endocytic pathways. Furthermore, the EGCG-loaded nanosystem (TDN-EGCG@GNP) facilitates efficient inner ear drug delivery by superior permeability through the biological barrier (round window membrane), maintaining high drug concentration within the inner ear. The TDN-EGCG@GNP actively overcomes the cell membrane, exhibiting hearing protection from noise insults via reduced lipid peroxidation in outer hair cells and spiral ganglion neurons. This work exemplifies how integrating diverse vector functionalities can overcome biological and cellular barriers in the inner ear, offering promising applications for inner ear disorders.

Free PCR virus detection via few-layer bismuthene and tetrahedral DNA nanostructured assemblies.

In this work we describe a highly sensitive method based on a biocatalyzed electrochemiluminescence approach. The system combines, for the first time, the use of few-layer bismuthene (FLB) as a platform for the oriented immobilization of tetrahedral DNA nanostructures (TDNs) specifically designed and synthetized to detect a specific SARS-CoV-2 gene sequence. In one of its vertices, these TDNs contain a DNA capture probe of the open reading frame 1 ab (ORF1ab) of the virus, available for the biorecognition of the target DNA/RNA. At the other three vertices, there are thiol groups that enable the stable anchoring/binding to the FLB surface. This novel geometry/approach enables not only the binding of the TDNs to surfaces, but also the orientation of the capture probe in a direction normal to the bismuthine surface so that it is readily accessible for binding/recognition of the specific SARS-CoV-2 sequence. The analytical signal is based on the anodic electrochemiluminescence (ECL) intensity of luminol which, in turn, arises as a result of the reaction with H2O2, generated by the enzymatic reaction of glucose oxidation, catalyzed by the biocatalytic label avidin-glucose oxidase conjugate (Av-GOx), which acts as co-reactant in the electrochemiluminescent reaction. The method exhibits a limit of detection (LOD) of 4.31 aM and a wide linear range from 14.4 aM to 1.00 µM, and its applicability was confirmed by detecting SARS-CoV-2 in nasopharyngeal samples from COVID-19 patients without the need of any amplification process.

A "signal off-on" fluorescence bioassay based on 2D-MoS2-tetrahedral DNA bioconjugate for rapid virus detection.

In this work we present the preparation of a 2D molybdenum disulphide nanosheets (2D-MoS2) and tetrahedral DNA nanostructures (TDNs) bioconjugate, and its application to the development of a bioassay for rapid and easy virus detection. The bioconjugate has been prepared by using TDNs carrying the capture probe labelled with 6-carboxyfluoresceine (6-FAM). As case of study to assess the utility of the assay developed, we have chosen the SARS-CoV-2 virus. Hence, as probe we have used a DNA sequence complementary to a region of the SARS-CoV-2 ORF1ab gene (TDN-ORF-FAM). This 6-FAM labelled capture probe is located on the top vertex of the tetrahedral DNA nanostructure, the three left vertices of TDNs have a thiol group. These TDNs are bounded to 2D-MoS2 surface through the three thiol groups, allowing the capture probe to be oriented to favour the biorecognition reaction with the analyte. This biorecognition resulting platform has finally been challenged to the detection of the SARS-CoV-2 ORF1ab gene sequence as the target model by measuring fluorescence before and after the hybridization event with a detection limit of 19.7fM. Furthermore, due to high sensitivity of the proposed methodology, it has been applied to directly detect the virus in nasopharyngeal samples of infected patients without the need of any amplification step. The developed bioassay has a wide range of applicability since it can be applied to the detection of any pathogen by changing the probe corresponding to the target sequence. Thus, a novel, hands-on strategy for rapid pathogen detection has proposed and has a high potential application value in the early diagnosis of infections causes by virus or bacteria.

Tetrahedral DNA Nanostructure-Engineered Paper-Based Electrochemical Aptasensor for Fumonisin B1 Detection Coupled with Au@Pt Nanocrystals as an Amplification Label.

Fumonisin B1 (FB1), as one of the highest toxicity mycotoxins, poses a serious threat to animal and human health, even at low concentrations. It is significant and challenging to develop a sensitive and reliable analytical device. Herein, a paper-based electrochemical aptasensor was designed utilizing tetrahedral DNA nanostructures (TDNs) to controllably anchor an aptamer (Apt), improving the recognition efficiency of Apt to its target. First, gold nanoparticles (AuNPs)@MXenes were used as a sensing substrate with good conductivity and modified on the electrode for immobilization of complementary DNA-TDNs (cDNA-TDNs). In the absence of FB1, numerous Apt-Au@Pt nanocrystals (NCs) was hybridized with cDNA and assembled on the sensing interface, which accelerated the oxidation of TMB with H2O2 and produced a highly amplified differential pulse voltammetry (DPV) signal. When the target FB1 specifically bound to its Apt, the electrochemical signal was decreased by releasing the Apt-Au@Pt NCs from double-stranded DNA (dsDNA). On account of the strand displacement reaction by FB1 triggering, the aptasensor had a wider dynamic linear range (from 50 fg/mL to 100 ng/mL) with a lower limit of detection (21 fg/mL) under the optimized conditions. More impressively, the designed FB1 aptasensor exhibited satisfactory performance in corn and wheat samples. Therefore, the TDN-engineered sensing platform opens an effective approach for sensitive and accurate analysis of FB1, holding strong potential in food safety and public health.

Noninvasive Framework Nucleic Acid Eye Drops for Retinal Administration.

Intravitreal injection is widely employed for the treatment of retinal diseases. However, it suffers from various drawbacks, including ocular trauma, risk of infection, and poor patient compliance due to frequent administrations. Due to the presence of barriers such as the cornea, it has been a challenge to develop efficient noninvasive ophthalmic eye drops that can reach the retina. Framework nucleic acids (FNAs), known for their excellent biocompatibility and precise, controllable shape and size, have been extensively utilized in drug delivery application. Here, we report the development of size- and shape-resolved fluorescent DNA frameworks for noninvasive retinal administration. Results show that tetrahedral DNA nanostructures (TDNs) with an edge length of 20 bp can reach the retina within 6 h with the highest efficiency. Moreover, this delivery method exhibits excellent biocompatibility. Our findings provide an approach for the development of localized treatment strategies for retinal diseases using FNA-based nanocarriers.

Dual-ratiometric aptasensor for simultaneous detection of malathion and profenofos based on hairpin tetrahedral DNA nanostructures.

Due to the diversification and complexity of organophosphorus pesticide residues brings great challenges to the detection work. Therefore, we developed a dual-ratiometric electrochemical aptasensor that could detect malathion (MAL) and profenofos (PRO) simultaneously. In this study, metal ions, hairpin-tetrahedral DNA nanostructures (HP-TDN) and nanocomposites were used as signal tracers, sensing framework and signal amplification strategy respectively to develop the aptasensor. Thionine (Thi) labeled HP-TDN (HP-TDNThi) provided specific binding sites for assembling Pb2+ labeled MAL aptamer (Pb2+-APT1) and Cd2+ labeled PRO aptamer (Cd2+-APT2). When the target pesticides were present, Pb2+-APT1 and Cd2+-APT2 were dissociated from the hairpin complementary strand of HP-TDNThi, resulting in reduced oxidation currents of Pb2+ (IPb2+) and Cd2+ (ICd2+), respectively, while the oxidation currents of Thi (IThi) remained unchanged. Thus, IPb2+/IThi and ICd2+/IThi oxidation current ratios were used to quantify MAL and PRO, respectively. In addition, the gold nanoparticles (AuNPs) encapsulated in the zeolitic imidazolate framework (ZIF-8) nanocomposites (Au@ZIF-8) greatly increased the catch of HP-TDN, thereby amplifying the detection signal. The rigid three-dimensional structure of HP-TDN could reduce the steric hindrance effect on the electrode surface, which could greatly improve the recognition efficiency of the aptasensor for the pesticide. Under the optimal conditions, the detection limits of the HP-TDN aptasensor for MAL and PRO were 4.3 pg mL-1 and 13.3 pg mL-1, respectively. Our work proposed a new approach to fabricating a high-performance aptasensor for simultaneous detection of multiple organophosphorus pesticides, opening a new avenue for the development of simultaneous detection sensors in the field of food safety and environmental monitoring.

Anchoring red blood cell with tetrahedral DNA nanostructure: Electrochemical biosensor for the sensitive signage of circulating tumor DNA.

Circulating tumor cells (CTCs), as a type of tumor, have attracted wide attention because of their characteristics of shedding from the primary tumor and spreading to other tissues and organs through peripheral blood. The circulating tumor DNA (ctDNA), the DNA released by CTCs and other tumor cells into the peripheral blood, was considered as a promising detection substance for clinical application. By utilizing the biocompatibility of red blood cells to realize the attachment of tetrahedral DNA (TDN), as well as the specific target recognition ability of TDN to enable efficient recognition of targets, a biocompatible electrochemical biosensor for effective and rapid detection of ctDNA was developed using methylene blue (MB) as the signal probe. The current signal and the logarithm of ctDNA concentration were linearly correlated in the range from 1 fM to 100 pM with the detection limit of 0.66 fM. With high specificity, the TDN-based biosensor can detect ctDNA efficiently in the real biological environment such as serum, which provided a potential opportunity for the early clinical diagnosis.

Applications of tetrahedral DNA nanostructures in wound repair and tissue regeneration.

Tetrahedral DNA nanostructures (TDNs) are molecules with a pyramidal structure formed by folding four single strands of DNA based on the principle of base pairing. Although DNA has polyanionic properties, the special spatial structure of TDNs allows them to penetrate the cell membrane without the aid of transfection agents in a caveolin-dependent manner and enables them to participate in the regulation of cellular processes without obvious toxic side effects. Because of their stable spatial structure, TDNs resist the limitations imposed by nuclease activity and innate immune responses to DNA. In addition, TDNs have good editability and biocompatibility, giving them great advantages for biomedical applications. Previous studies have found that TDNs have a variety of biological properties, including promoting cell migration, proliferation and differentiation, as well as having anti-inflammatory, antioxidant, anti-infective and immune regulation capabilities. Moreover, we confirmed that TDNs can promote the regeneration and repair of skin, blood vessels, muscles and bone tissues. Based on these findings, we believe that TDNs have broad prospects for application in wound repair and regeneration. This article reviews recent progress in TDN research and its applications.

Treatment effect of DNA framework nucleic acids on diffuse microvascular endothelial cell injury after subarachnoid hemorrhage.

OBJECTIVES: The purpose of this study was to investigate the treatment effect and molecular mechanism of tetrahedral framework nucleic acids (tFNAs), novel self-assembled nucleic acid nanomaterials, in diffuse BMEC injury after SAH. MATERIALS AND METHODS: tFNAs were synthesized from four ssDNAs. The effects of tFNAs on SAH-induced diffuse BMEC injury were explored by a cytotoxicity model induced by hemin, a breakdown product of hemoglobin, in vitro and a mouse model of SAH via internal carotid artery puncture in vivo. Cell viability assays, wound healing assays, transwell assays, and tube formation assays were performed to explore cellular function like angiogenesis. RESULTS: In vitro cellular function assays demonstrated that tFNAs could alleviate hemin-induced injury, promote angiogenesis, and inhibit apoptosis in hemin cytotoxicity model. In vivo study using H&E and TEM results jointly indicated that the tFNAs attenuate the damage caused by SAH in situ, showing restored number of BMECs in the endothelium layer and more tight intercellular connectivity. Histological examination of SAH model animals confirmed the results of the in vitro study, as tFNAs exhibited treatment effects against diffuse BMEC injury in the cerebral microvascular bed. CONCLUSIONS: Our study suggests the potential of tFNAs in ameliorating diffuse injury to BMECs after SAH, which laid theoretical foundation for the further study and use of these nucleic acid nanomaterials for tissue engineering vascularization.

Ionic Current Fluctuation and Orientation of Tetrahedral DNA Nanostructures in a Solid-State Nanopore.

Understanding the dynamic behavior of a nanostructure translocating through a nanopore is important for various applications. In this paper, the characteristics in ion current traces of tetrahedral DNA nanostructures (TDN) translocating through a solid-state nanopore are examined, by combined experimental and theoretical simulations. The results of finite element analysis reveal the correlation between orientation of TDN and the conductance blockade. The experimentally measured fluctuations in the conductance blockade, expressed as voltage-dependent histogram profiles, are consistent with the simulation, revealing the nature of a random distribution in orientation and weak influence of electrostatic and viscous torques. The step changes in orientation of a TDN during translocation are further explained by the collision with the nanopore, while the gradual changes in orientation illustrate the impact of a weak torque field in the nano-fluidic channel. The results demonstrate a general method and basic understanding in the dynamic behavior of nanostructures translocating through solid-state nanopores.

Tetrahedral DNA nanostructures for effective treatment of cancer: advances and prospects.

Recently, DNA nanostructures with vast application potential in the field of biomedicine, especially in drug delivery. Among these, tetrahedral DNA nanostructures (TDN) have attracted interest worldwide due to their high stability, excellent biocompatibility, and simplicity of modification. TDN could be synthesized easily and reproducibly to serve as carriers for, chemotherapeutic drugs, nucleic acid drugs and imaging probes. Therefore, their applications include, but are not restricted to, drug delivery, molecular diagnostics, and biological imaging. In this review, we summarize the methods of functional modification and application of TDN in cancer treatment. Also, we discuss the pressing questions that should be targeted to increase the applicability of TDN in the future.

Mono-dispersed nano-hydroxyapatite based MRI probe with tetrahedral DNA nanostructures modification for in vitro tumor cell imaging.

Taking advantage of the superior biocompatibility, good stability in a wide pH and temperature range, as well as its strong affinity with DNA of hydroxyapatite (HAp), tetrahedral DNA nanostructures (TDNs) conjugated with AS1411 aptamer (anti-nucleolin overexpressed on tumor cell membranes) were employed as affinity ligands to construct a novel mono-dispersed HAp based probe with Gd3+ doping (Apt-TDNs-GdHAp) for MR imaging. The adsorption of TDNs on the nano-HAp surface facilely accomplished the construction of the Apt-TDNs-GdHAp probes. Meanwhile, the use of hydrophilic TDNs not only favored the phase-transfer from the oil phase to the aqueous phase, but also enhanced the mono-dispersion of this probe due to the well-ordered distribution of TDNs on the surface of nano-HAp. Moreover, Apt-TDNs-GdHAp probe with a better mono-dispersion and crystalinity achieved twice higher longitudinal relaxivity (r1 value) than that of GdHAp synthesized by microwave-assisted method (Microwave-GdHAp), exhibiting much more excellent T1-weighted imaging performance. With the introduction of TDNs, the stability and the tumor-targeting accessibility were also greatly improved, showing its great potential for further bio-applications.

Size-Independent Transmembrane Transporting of Single Tetrahedral DNA Nanostructures.

DNA nanostructures have attracted considerable attention as drug delivery carriers. However, the transmembrane kinetics of DNA nanostructures remains less explored. Herein, the dynamic process of transporting single tetrahedral DNA nanostructures (TDNs) is monitored in real time using a force-tracing technique based on atomic force microscopy. The results show that transporting single TDNs into living HeLa cells need ≈53 pN force and ≈25 ms duration with the average speed of ≈0.6 µm s-1. Interestingly, the dynamic parameters are irrelevant to the size of TDNs, while the larger TDNs rotated slightly during the transporting process. Meanwhile, both the results from single-molecule force tracing and ensemble fluorescence imaging demonstrate that the different size TDNs transmembrane transporting depends on caveolin-mediated endocytosis.

Review of craniofacial regeneration in China.

AIM: Tissue engineering has been recognised as one of the most effective means to form a new viable tissue for medical purpose. Tissue engineering involves a combination of scaffolds, cells, suitable biochemical and physicochemical factors, and engineering and materials methods. This review covered some biomedicine, such as biomaterials, bioactive factors, and stem cells, and manufacturing technologies used in tissue engineering in the oral maxillofacial region, especially in China. MATERIALS AND METHODS: Data for this review were identified by searches of Web of Science and PubMed, and references from relevant articles using the search terms "biomaterials", "oral tissue regeneration", "bioactive factors" and "stem cells". Only articles published in English between 2013 and 2018 were included. CONCLUSION: The combination of stem cells, bioactive factors and 3D scaffolds could be of far-reaching significance for the future therapies in tissue repair or tissue regeneration. Furthermore, the review also mentions issues that need to be solved in the application of these biomedicines.

Short-chain oligonucleotide detection by glass nanopore using targeting-induced DNA tetrahedron deformation as signal amplifier.

Glass capillary nanopore has been developed as a promising sensing platform for bioassay with single-molecule resolution. Although the diameter of glass capillary nanopore can be easily tuned, direct event-readouts of small biomacromolecules, like short-chain oligonucleotide fragments (within ∼20 nucleotides) remain great challenge, which limited by the configuration of the conical-shaped nanopore and the instrumental temporal resolution. Here, we exploit a smart strategy for glass nanopore detection of short-chain oligonucleotides by using relatively big-sized tetrahedral DNA nanostructures as a signal amplifier, which can amplify the signals and retard the translocation speed meanwhile. The tetrahedral DNA nanostructure with a hairpin loop sequence in one edge, undergoes a shape transformation upon the complementary combination of the target oligonucleotides, in which the presence of short-chain target oligonucleotide can be readout due to obvious variation in amplitude of ion current pulse that caused by volume change of the DNA tetrahedral. Therefore, this strategy is promising for extending glass nanopore sensing platform for sensitive detection of short-chain oligonucleotides.

The Clearance Effect of Tetrahedral DNA Nanostructures on Senescent Human Dermal Fibroblasts.

Senescent cells are characterized by their resistance to apoptosis, and upon their long-term survival senescent cells affect tissue function and eventually become deleterious to the organism. Thus, far, it has been gradually accepted that clearance of these senescent cells could reduce tissue dysfunction. This study aimed to investigate biological effects of tetrahedral DNA nanostructures (TDNs) on senescent cells. The results revealed a different biological effect of TDNs, and their clearance effect on senescent cells. TDNs can induce phenotypic changes in senescent cells, suppressing antiapoptotic BCL-2 family proteins and upregulating BAX, a BCL-2 family proapoptotic protein, to influence the expression levels and function of downstream proteins. Consequently, cytochrome C releasing promoted cleavage-mediated activation of pro-caspase-3 and its nuclear translocation from the cytoplasm to mediate apoptosis. The present results provide a foundation for further studies on the application of TDNs in studies on aging.

Tetrahedral DNA Nanostructure Promotes Endothelial Cell Proliferation, Migration, and Angiogenesis via Notch Signaling Pathway.

The problem of tissue vascularization is one of the obstacles that currently restricts the application of tissue engineering products to the clinic. Achieving tissue vascularization and providing adequate nutrients for tissues are an urgent problem to build complex and effective tissue-engineered tissues and organs. Therefore, the aim of this study was to investigate the effect of tetrahedral DNA nanostructures (TDNs), a novel and biocompatible nanomaterial, on angiogenesis. The results showed that TDNs can enter into endothelial cells (ECs) and promote EC proliferation, migration, tube formation, and expressions of angiogenic growth factors at the concentration of 250 nmol L-1, which was accompanied by activation of the Notch signaling pathway. These results provided a theoretical basis for the further understanding and potential use of TDNs in tissue engineering vascularization.

Neuroprotective Effect of Tetrahedral DNA Nanostructures in a Cell Model of Alzheimer's Disease.

Accumulating evidence supports the abnormal deposition of amyloid ß-peptide (Aß) as the main cause of Alzheimer's disease (AD). Therefore, fighting against the formation, deposition, and toxicity of Aß is a basic strategy for the treatment of AD. In the process of in vitro nerve cell culture, screening out drugs that can antagonize a series of toxic reactions caused by ß-amyloid deposition has become an effective method for the follow-up treatment of AD. Our previous studies showed that tetrahedral DNA nanostructures (TDNs) had good biocompatibility and had some positive effects on the biological behavior of cells. In this study, the main aim of our work was to explore the effects and potential mechanism of TDNs in protecting neuronal PC12 cells from the toxicity of Aß. Our study demonstrated that TDNs can protect and rescue PC12 cell death through Aß25-35-induced PC12 cell apoptosis. Further studies showed that TDNs significantly improved the apoptosis by affecting the abnormal cell cycle, restoring abnormal nuclear morphology and caspase activity. Western blot analysis showed that TDNs could prevent the damage caused by Aß deposition by activating the ERK1/2 pathway and thus be a potential therapeutic agent with a neuroprotective effect in Alzheimer's disease. Our finding provides a potential application of TDNs in the prevention and treatment of AD.

Aflatoxin B1 Electrochemical Aptasensor Based on Tetrahedral DNA Nanostructures Functionalized Three Dimensionally Ordered Macroporous MoS2-AuNPs Film.

In food safety evaluation, aflatoxin B1 (AFB1) is an important indicator. In this work, we developed an AFB1 electrochemical aptasensor based on a tetrahedral DNA nanostructures (TDNs) immobilized three dimensionally ordered macroporous MoS2-AuNPs hybrid (3DOM MoS2-AuNPs) recognition interface and horseradish peroxidase (HRP) functionalized magnetic signal amplifier. To greatly enhance the recognition efficiency, sensitivity, and stability of the aptasensor, the AFB1 aptamer-incorporated TDNs were ingeniously combined with the 3DOM MoS2-AuNPs film for the construction of the sensing interface. The aptamers would release from the electrode surface after they reacted with AFB1, and then the hybridization-free TDNs formed. Thus, the biocomposite of DNA helper strands (H1)/HRP functionalized AuNPs-SiO2@Fe3O4 nanospheres would combine with the hybridization-free TDNs due to the hybridization of H1 and TDNs. The more AFB1 existed in the solution, the more H1/HRP-AuNPs-SiO2@Fe3O4 could be combined onto the 3DOM MoS2-AuNPs surface. The current response coming from HRP-catalyzed reduction of H2O2 using thionine (Thi) as electrochemical probe was proportional with the AFB1 concentration. Upon optimal conditions, the aptasensor showed specificity for AFB1, achieving a good linear range of 0.1 fg/mL-0.1 µg/mL and the detection limit of 0.01 fg/mL. Furthermore, the developed aptasensor was also applied for detecting AFB1 content in rice and wheat powder samples, obtaining good results in conformity with those achieved from the high-performance liquid chromatography tandem mass spectrometry (HPLC-MS) method.